Absolute Origin

catman · September 21, 2021, 10:57am

Hi I would like to get the Lightburn software for my CO2 DSP system that has been upgraded to a Ruida controller. I used the Lightburn test to verify the basic functions and all seems ok.

However I am missing one thing in the documentation and also I could not find a clear answer in the forum for my issue.
The laser has the end switches back and right. It homes to there and it starts its coordinate system there. The jog buttons move to the right direction. I think the setup of the machine data is correct and matches with the descriptions in the Lightburn manual.

Now I expected that I can set my work space origin in Lightburn to start at any position I like. Looking at the settings indeed I can set the origin to any of the 4 corners or in other words use any of the 4 quadrants I like.
But setting my work space to abolute origin back left corner and placing a rectangle cut close to the orign, the laser mirrored it and cut it at close to the right and back corner. it seems the coordinates were not transformed by Lightburn.

I was a bit stunned, because I thought thats quite a basic feature. Even the not really great china software that came with the controller does that. Why would Lightburn not? Obviously the controller LCD would display other coordinates that the software GUI but can that be a reason against that feature?

I am coming across this because all my other CNC machines and printers have the coordinate origin upper left (aka back left in the laser), so only in Lightburn this would be mirrored. All guides I made with the old controller have the coordinates with the other origin on it. So I’d get quite a usability impact by not being able to move that over.

I hope I am not seeing the obvious and the feature is there but I am just too stupid to see it.

bernd.dk · September 21, 2021, 12:21pm

github.com

LightBurnSoftware/Documentation/blob/master/CoordinatesOrigin.md#user-origin

[Return to main page](README.md)

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# Coordinates and Job Origin

There are a couple different ways to tell LightBurn how to cut the project within the work area of your machine.  You choose them in the "Start From" box on the Laser tab:

![Start From](./img/CoordinatesStartFrom.png)

## Absolute Coordinates

**Absolute Coordinates** is the simplest - The page grid you see in the main editing window represents your machine's work area.  Anything you place in that area will be cut in the corresponding place on your machine.  Users with small lasers like the K40 will likely find this the simplest and most intuitive option.

In the image below, the two circles placed in the middle of the work area will be cut in the middle of the machine work area.  The green square in the lower-left of the image represents the Job Origin, and the red square in the same place shows the Machine Origin.  In "Absolute Coordinates" these are always in the same place.

![Coordinates Absolute Position](./img/CoordinatesAbsolute.png)

## Current Position

This file has been truncated. show original

It might help you.

catman · September 21, 2021, 12:40pm

Thanks for the link. Sorry when I was unclear, but I think this page does not adress my problem.

I think closest is the following section, but there is no further information:
“The green square in the lower-left of the image represents the Job Origin, and the red square in the same place shows the Machine Origin. In “Absolute Coordinates” these are always in the same place”

I would need to move the red square to another corner without modifying the machine hardware so that an object like a circle is cut in the same place than on the screen.

bernd.dk · September 21, 2021, 1:00pm

can it light up the mystery?

catman · September 21, 2021, 1:22pm

Thanks a lot. The first part of the video addresses the origin issue, but just demonstrates what I observe without explaining it. The statement “absolute origin is not where homing is” and “absolute origin ist mostly always lower left” are imho not that helpful. It looks from what he demonstrates and what I see that the absolute origin is determined by the controllers coordinates used. He could say “check on the LCD (if you have one) where the machine shows 0,0 and put the absolute origin there.” Homing is not relevant. I think I understand what he is saying.

My question starts where those descriptions end. I have a controller hat puts its (0,0) at top right. Is there a way that Lightburn uses my workspace info and offers me a workspace with origin top left. In the background each X coordinate is just subtraced by my workspace width before sending to the controller. Not really a complex function, so I would expect that its implemented somewhere …?

bernd.dk · September 21, 2021, 1:45pm

On my K40, the machine origin is top left, this is also where my end stops are located.
However, it could be interesting to hear other users of the same machine type as yours how they handle your question.
(you have only written CO2 and Ruida in your profile, is it a “normal” 30-100 Watt Chinese or a home-built machine?)

catman · September 21, 2021, 2:48pm

No its a normal Chinese laser, but I upgraded the old controller with a RD6442G. The home is also at the end stop position which is top right. Maybe there is a way to switch the origin on the controller, but I have not found it out yet.

bernd.dk · September 21, 2021, 3:16pm

Hope you find the right solution
Good luck

Rick · September 21, 2021, 6:51pm

For Homing behavior for a Ruida controller, this is worth review: Configuring a Ruida - LightBurn Software Documentation

catman · September 21, 2021, 7:54pm

Hi Rick, tanks a lot for point this out.
I did read that for setting up the machine. In the mean time I have been through the controller manual again, an there is not option to swap the origin on the controller itself.

Can you confirm whether or not such a function is available in Lightburn? Or is it unclear what I mean?

Rick · September 21, 2021, 9:31pm

Your physical laser Home position, also known as Machine Origin, and the ‘Origin’ in the ‘Device Settings’ window in LightBurn need to match to have the coordinate system behave as expected when controlling from LightBurn.

The ‘Start From’ and ‘Job Origin’ section, found in the ‘Laser’ window, is offered to allow control of each job and where the laser will start the job from. Coordinates and Job Origin - LightBurn Software Documentation

catman · September 22, 2021, 11:58am

So there is not such function to swap the absolute coordinates.

May I kindly ask whether there is a specific reason that there is not such function today, or did just no one ever requested such a thing (or no one everd deemed it necessary)?

system · October 22, 2021, 11:58am

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